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From: kwallich@hpsmtc1.HP.COM (Ken Wallich)
Newsgroups: comp.sys.mac
Subject: Re: MAC 256K SIMMs --> Mac ][  HELP
Message-ID: <11540041@hpsmtc1.HP.COM>
Date: Tue, 10-Nov-87 12:39:29 EST
Article-I.D.: hpsmtc1.11540041
Posted: Tue Nov 10 12:39:29 1987
Date-Received: Fri, 13-Nov-87 07:23:39 EST
References: <5134@cisunx.UUCP>
Organization: Hewlett Packard, Cupertino
Lines: 59


jasst3@cisunx.UUCP (Jeffrey A. Sullivan) / 11:07 am  Nov  9, 1987 /

>Question is this:  Can I just slip those 2 256K SImms into the second bank
>of the ]['s memory banks (along with another pair of 256K SIMMs) and have
>an extra meg?  Are the speeds of the chips OK?

The Mac II comes with 120ms chips.  The SE comes with 150ms chips.
The Mac II will run with ALL 120ms chips, or ALL 150ms chips, but if you 
combine the two, it will only recognize the faster (120ms) chips.  You could
put 120ms chips in your SE, but I don't know how well this works (I have a
MacII :-).  Also I assume you mean 4 256K SIMMs to make a Meg.  Even though
they sell them in 2's, 1 SIMM is either 256K or 1MB depending on the chips.

>Also, is it possible to un-do a 2M expansion to an SE so I could use the 2
>1M SIMMs in the ][ and put the 256K SIMMs back in the SE?

The same chip speeds apply to the 1MB chips.  See the previous caviats,
or is that caviar?

>This raises another question:  What are the allowable increments for adding
>SIMMs to a Mac ][?  Can I pop in 1M SIMMs 1 at a time to bump my memory up
>by 1 Meg increments?  What does the ][ come with: 4 256K SIMMs?

The II (][ reminds me of a *gag* Apple ][) does indeed come with 4 256K SIMMs
unless you order it with more, in which case the dealer will insall the 
upgrade, and keep the 256K chips for someone else (be carefull not to pay for 
them!).  You cannot "pop" 1MB SIMMs 1 at a time :-(.  There are 2 "banks"
of memory, and each must be fully populated (4 SIMMs) with the same density
chips.  In multiple density configurations, the highest density chips must
be in the lowest bank (bank "A").

Possible memory configurations are as follows (this is reposted from something
someone else posted a month or two ago, sorry I don't remember who):

RAM         Bank A                  Bank B               What To Order
-----       -------                 -------              -------------
1M          Four 256K SIMMs         Empty                Factory Standard
2M          Four 256K SIMMs         Four 256K SIMMs      1 - MO218
4M          Four  1M  SIMMs         Empty                2 - MO219
5M          Four  1M  SIMMs         Four 256K SIMMs      2 - MO219
8M          Four  1M  SIMMs         Four  1M  SIMMs      4 - MO219

Where:
  MO218 - 4 256K SIMMs 
  MO219 - 2 1Mb  SIMMS 

----------

Hope this helps you out!


--------------------
Ken Wallich			*My views are mine, and mine alone*
Consultant			"Camelot! Camelot! -- It's only a model"	
DCI 				kwallich@hpsmtc1.HP.COM
@Hewlett Packard		...hplabs!hpsmtc1!kwallich

"Your Delta Tou Kai name is ... Flounder"